In process equipment, including components containing one or more of gases, liquids and/or powders, such as for instance spray drying chambers, cyclones, bag filters, fluid bed chambers, process chambers, containers, tanks, ducts or any similar vessel, regular cleaning is necessary in order to meet the requirements set by governmental regulations and/or manufacture specifications. Such cleaning is carried out at suitable intervals to avoid product degradation, contamination and build-up of deposits in the components. In order to keep the time needed for cleaning as short as possible without the disassembly of any components, cleaning-in-place (CIP) systems have been developed, which make it possible to clean the interior of such components in an effective manner and thereby minimize cleaning time and maintain high plant productivity. The CIP systems are possibly automated in order to render the cleaning even more efficient, thus making use of computer programmed cleaning sequences. In addition to providing an increased degree of cleaning, efficient cleaning entails that less CIP fluid is used. This in turn provides for a better overall process economy, but is above all more environmentally sound, as the amount of CIP fluid to be filtered and possibly cleaned and/or disposed of is reduced as well.
Use of nozzles for distributing cleaning fluid in such CIP systems is well-established and examples of cleaning nozzles in the prior art are numerous. The nozzle or nozzles should be located in such a manner in the component that the required area of the inner walls of the component is covered by cleaning fluid during the cleaning procedure to an appropriate extent. This may be achieved as in US 2008/0053482 A1, in which a plurality of stationary nozzles is located on a shaft inside the rotatable vessel and the individual nozzles are directed to different sections of the vessel. In the kind of nozzle disclosed in DE 102 08 237 C1 and U.S. Pat. No. 5,096,122, a rotatable nozzle head is connected to a stationary nozzle body. Off-center apertures formed in the nozzle head cause the nozzle head to rotate by the reaction forces exerted by the cleaning fluid. In this manner, a larger area of the interior of the vessel may be covered by a single nozzle. A structurally similar nozzle is disclosed in U.S. Pat. No. 4,913,346, however, the driving force for rotating the nozzle head is provided by the transmission of a magnetic force.
The above-mentioned nozzles are at least partly permanently located inside the vessel to be cleaned. This configuration is not desirable or possible in all applications, as the nozzles themselves firstly may cause disturbance to the process, and secondly they are prone to the formation of deposits and possible contamination; this applies especially to dairy plants, in which the hygiene requirements are particularly strict, not least in the infant food sector of this industry.
In a commercially available nozzle traded by GEA Niro, this disadvantage is alleviated by a nozzle design, in which the nozzle body has a flange welded to the wall of a component such as a vessel of a plant, and the nozzle insert is movable from a first or retracted position, in which a front surface of the nozzle insert is substantially flush with the flange of the nozzle body, to a second or an advanced position, in which the front of the nozzle insert protrudes into the vessel. The nozzle insert is fitted with a spray ring provided with a number of off-center apertures that are exposed in the advanced position. When cleaning fluid is supplied to the nozzle, the spray ring rotates according to the feed pressure. The translational movement of the nozzle between its retracted and advanced positions may be carried out by the pressure of the cleaning fluid itself, or the nozzle may be pneumatically operated.
Although this nozzle design has proven well over a number of years and provides a well-functioning compromise between the need to have a smooth front surface of the nozzle during operation and the desire to spray in several directions during cleaning, it has some disadvantages. For instance, due to the design of the nozzle, the spray angle is limited to a circumferential sector ranging from 0 to approximately 60 or 70 degrees. Thus, spraying in angles close to the axial direction is not possible. This must be considered when designing the configuration and number of the individual nozzles in the vessel and nozzles must be provided to cover the area opposite each individual nozzle, thus increasing the overall number of nozzles necessary to clean the vessel. Furthermore, the cleaning effect is dependent on the self-rotation of the spray ring, and if small impurities or deposits get caught in any of the rotating parts of the nozzle, rotation of the spray ring may be impeded, possibly to such an extent that the spray ring does not rotate at all.
CIP systems are used in both food, dairy, pharmaceutical and chemical industries. The cleaning fluid may be water or possibly an alternating use of water and suitable detergents or cleaning agents. For some purposes, CIP may be used in combination with a further sterilization process.